OBD2 cable and usb-serial adapter

Anyone ever gotten this working?
I have an aten usb-serial adapter and a vag-com cable that i'm borrowing from my friend which has the standard iso pinouts, but can't connect to my ecu whatsoever.... i'm thinking it's the adapter... too lazy to unplug my touchscreen from com1 to test out the other com port

Anybody got a good USB to serial coverter that they _know_ works with the http://www.obddiagnostics.com/ setup? I'm ready to order that thing, but not until I have a known good USB -> serial device in my hand....and a search for "USB Serial converter OBD" gave me no hits.